Former CIA chief John Brennan on Friday predicted "rough waters ahead," particularly on international issues, saying President Trump is "unstable, inept, inexperienced, and also unethical."

In an interview with MSNBC's "Deadline: White House," Brennan told host Nicolle Wallace that the president was "ill prepared" to take on the duties of commander in chief, particularly growing military aggression from Russia and North Korea.

"It is no secret to anybody that Donald Trump was very ill prepared and unexperienced in terms of dealing with matters that a head of state needs to deal with, head of government, and I think this is now coming to roost," Brennan said.